鄂尔多斯盆地陕北斜坡东部三叠系长6油藏分布规律

Petroleum Accumulation and Distribution in Triassic Chang-6 Reservoir in Eastern North Shaanxi Slope, Ordos Basin

传统认为,鄂尔多斯盆地陕北斜坡为一平缓的西倾单斜,构造简单,因此包括长6油藏在内的三叠系延长组油藏的形成和分布主要受沉积相控制,油藏类型主要为岩性油藏,构造等其它因素对三叠系延长组油藏的形成和分布不起主要控制作用。研究认为,三角洲分流河道砂体是长6油藏形成的基础,鼻状隆起背景是长6油藏油气富集的重要条件,水动力则可能是长6油藏形成的一个重要圈闭因素。因此,长6油藏的类型复杂多样,主要有以构造-岩性、构造-水动力为主的复合油藏,次为岩性油藏。

Traditionally, it was believed that the north Shaanxi slop in Ordos basin was a gentle west-tipping monoeline. The formation and distribution of Triassic Yanehang reservoir including Chang-6 reservoir were mainly controlled by sedimentary faeies, dominated by lithological reservoir, hence the structural factor and others did not play major controlling roles on Yanehang reservoir＇s formation and distribution in this area. This study shows that the foundation forming Chang-6 reservoir is the delta distributary channel sands, the necessary condition of petroleum enrichment in Chang-6 reservoir is the nose-like uplift setting and the hydrodynamic environment is its important trapping factor. Therefore, Chang-6 reservoir is in various types, dominated by complex reservoirs including structural-lithologic reservoir and structural-hydrodynamic reservoir, sub-dominated by lithologic reservoir.